Consolidated Statements Of Cash Flows - USD ($) $ in Millions	2 Months Ended	4 Months Ended	6 Months Ended
	Jun. 30, 2021	Apr. 30, 2021	Jun. 30, 2020
Successor [Member]
Cash flows provided from (used by) operating activities:
Net income (loss)	$ 99
Adjustments to reconcile net income (loss) to net cash provided from (used by) operating activities:
Depreciation and amortization	179
Other adjustments	(5)
Deferred income taxes	37
Change in accounts receivable	12
Change in accounts payable and other liabilities	51
Change in prepaid expenses, income taxes and other assets	7
Net cash provided from (used by) operating activities	380
Cash flows provided from (used by) investing activities:
Capital expenditures	(269)
Net cash provided from (used by) investing activities	(269)
Cash flows provided from (used by) financing activities:
Long-term debt principal payments	(4)
Finance lease obligation payments	(4)
Other	1
Net cash provided from (used by) financing activities	(7)
Increase (Decrease) in cash, cash equivalents and restricted cash	104
Cash, cash equivalents and restricted cash at the beginning of the period	940
Cash, cash equivalents and restricted cash at the end of the period	1,044	$ 940
Cash paid during the period for:
Interest	84
Income tax payments, net	24
Predecessor [Member]
Cash flows provided from (used by) operating activities:
Net income (loss)		4,541	$ (367)
Adjustments to reconcile net income (loss) to net cash provided from (used by) operating activities:
Depreciation and amortization		506	812
Pension settlement costs			159
Stock-based compensation expense		(1)	2
Amortization of deferred financing costs			11
Non-cash reorganization items, net		(5,467)	85
Other adjustments		1	2
Deferred income taxes		(148)	(92)
Loss on disposal of Northwest Operations			160
Change in accounts receivable		36	23
Change in accounts payable and other liabilities		(168)	278
Change in prepaid expenses, income taxes and other assets		46	(123)
Net cash provided from (used by) operating activities		(654)	950
Cash flows provided from (used by) investing activities:
Capital expenditures		(500)	(511)
Proceeds from sale of Northwest Operations			1,131
Proceeds on sale of assets		9	5
Other		1	3
Net cash provided from (used by) investing activities		(490)	628
Cash flows provided from (used by) financing activities:
Long-term debt principal payments		(1)	(5)
Proceeds from long-term debt borrowings		225
Financing costs paid		(4)	(19)
Finance lease obligation payments		(7)	(13)
Other		(16)
Net cash provided from (used by) financing activities		197	(37)
Increase (Decrease) in cash, cash equivalents and restricted cash		(947)	1,541
Cash, cash equivalents and restricted cash at the beginning of the period	$ 940	1,887	809
Cash, cash equivalents and restricted cash at the end of the period		940	2,350
Cash paid during the period for:
Interest		84	427
Income tax payments, net		9	1
Reorganization items, net		$ 1,397	$ 34